Fiber reinforced thermoplastics are well known. Reinforcing fibers may be short (e.g. chopped fiberglass) or long continuous fibers. Cogswell, "The Processing Science of Thermoplastic Structural Composites", Intern. Polymer Processing,1 (1987) 4, pp. 157-165 illustrates the latter. Specifically, Cogswell describes polyether etherketone (PEEK) reinforced with carbon fibers. Cogswell further teaches that the composite may be in the form of a laminate of two or more layers or plies, and that the carbon fibers in adjacent layers may be oriented in different directions. Carbon fibers are formed separately and are thereafter incorporated into the thermoplastic matrix by conventional means.
U.S. Pat. No. 4,820,568 to Harpell et al discloses a multilayer composite comprising a plurality of prepreg layers, in which layer comprises high strength preformed fibers of conventional materials (e.g., carbon, graphite, cellulose or metal) in a polymer matrix. The fibers are oriented in the same direction.
U.S. Pat. Nos. 4,728,698 and 4,835,047, both to Isayev, et al., disclose liquid crystal fiber reinforced polymer composites in which the liquid crystal fibers are formed in situ in a matrix of flexible chain thermoplastic polymer. The essentially unidirectionally oriented fibers are formed by application of high strain rate mixing conditions.